Electrical surge arrester



May 8, 1951 C- A. FOX

ELECTRICAL SURGE ARRESTER Filed April 25, 1947 2 Sheets-Sheet 1 INVENTOR CHARLES ADIN FOX ATTORNEY May 8, 1951 c, ox 2,551,592

ELECTRICAL SURGE ARRESTER Filed April 25, 1947 2 Sheets-Sheet 2 FIG. 2

/7" I 20 l 5 /7 /r 25 I Z, I I LZZ 2a 2a 28 W1 28 INVENTOR FIG. 3 CHARLES ADIN Fox ATTORNEY Patented May 8, 1951 ELECTRICAL SURGE ARRESTER Charles Adin Fox, Oakland Village, Mo., assignor to James R. Kearney Corporation, St. Louis, Mo., a corporation of Missouri Application April 25, 1947, Serial No. 743,746

5 Claims. 1

This invention relates generally to electrical protective devices which are adapted for use in protecting electrical circuits, and the equipment associated therewith, from the damaging effects of surges resulting from 1ightning and other causes, the predominant object of the invention being to provide an electrical protective device of this type which includes spaced elements that provide an air gap, and which is of such improved construction and arrangement that heavy surges will not permanently disturb the setting of the air gap.

Prior to this invention, protective devices of the surge arrester type have been employed which were provided each with an air gap produced by spaced elements that were rigidly secured in place. In the use of such a surge arrester it has been found that When an arc was formed across the air gap by a heavy surge there was a tendency for one or the other of the spaced gap-producing elements, or both thereof, to be permanently bent, or otherwise displaced, so that the width of the air gap was increased. The precise reason for this tendency for a heavy surge to permanently alter the width of the air gap by bending one or the other of the spaced gap-producing elements, or both thereof, has not been definitely determined, but it is the theory of electrical engineer that the lines of force moving about an arc flowing across the air gap tends to elongate the arc and act against the spaced gap-producing elements in a manner to widen the gap. Obviously, the efficiency a surge arrester whose air gap has been altered, as indicated above, is very greatly effected, as surges which should be but are not controlled by the surge arrester because of its widened gap, frequently do damage to the circuit in which the surge arrester is inter-- posed.

The surge arrester of the present invention is of such improved construction and arrangement that the difficulties recited above are eliminated in the operation of said surge arrester, this result being attained by mounting at least one of the gap-producing elements of the surge arrester for such movement that the air gap may be increased on passage thereacross of a heavy surge and so that said movably mounted element will return to its normal position after the surge has been bypassed. Thus, while passage across the air gap of the surge arrester of a heavy surge may increase the width of said air gap during such passage of the heavy surge, the width of the air gap is not permanentlyaltered, as was frequently the case heretofore, out, instead, the movable gapproducing element returns to its normal position after being moved by a heavy surge so as to provide an air gap of the proper setting for efliciently lay-passing subsequent surges which are imposed on the protected circuit.

Fig. 1 is a side elevation of the improved surge arrester of the present invention, the hanger for the surge arrester and the incoming and outgoing electrical conductors being broken away.

Fig. 2 is a fragmentary front elevation taken on line 2-2 of Fig. 1.

Fig. 3 is an enlarged horizontal section taken on line 3-3 of Fig. 1.

Fig. 4 is an enlarged horizontal section taken on line 4- of Fig. 1.

Fig. 5 is an enlarged horizontal section taken on line 5-5 of Fig. 1.

In the drawings, wherein is shown for purposes of illustration, merely, one embodiment of the invention, A designates the improved surge arrester generally. The particular surge arrester illustrated by the drawings comprises an insulator I, of the petticoat type, which is provided with a suitable hanger l and has mounted at its upper end an upper terminal 2. The upper terminal 2 has secured to its upper end portion, by means of a suitable connector 3, an incoming conductor Ca, and said upper terminal includes a block 130*- tion 4 through which an opening 4 is formed. The upper terminal supports an element 5 which is shaped as is shown in Fig. 1; that is to say said element '5 includes a horizontal portion 5a, a portion of which is extended through the opening 4' of the block portion A of the upper terminal 2, a downwardly and outwardly bent portion db, and an upwardly and inwardly extended portion 50. The element ii is preferably formed from rod material and it is secured to the block portion t of the upper terminal 2 by a clamping bolt E.

Mounted on the insulator l at a point beneath the upper terminal 2 is a supporting member 7 which is formed from heavy wire or rod material. The member l includes opposed arcuate portions 8 which are seated at the base of an annular groove of the insulator l between an adjacent pair of the ribs thereof partially embrace a portion of the insulator (see Fig. 3). Projected rearwardly from the arcuate portions 8 of the supporting member 2 is a pair of spaced extensio-ns 8 which have eyes iii formed at their rear ends, the shank of the bolt of a bolt and nut assembly it being :itended through said eyes and said bolt and nut assembly serving to draw the extensions 9 toward each other so as to cause the arcuate portions 2 to securely grip the insulator I. The supporting member '1 includes transversely spaced portions 12 which extend forwardly from the arcuate portions 8, these portions i2 being flared slightly throughout their outer portions as indicated at 52' in Fig. 3. The material of which the member l is formed is bent inwardly at the outer ends of the flared portions 52 to provide arcuate outer portions 53, extended rearwardly from said arcuate outer portions are-inner portions it whose rear portions are disposed in assrsea substantial parallelism with respect to the portions l2 of said member I. The portions [2 and the rear portions of the inner portions it of the member 1 are embraced by a hand I which retains said portions in their proper related positions.

Supported by the supportin member I is an element I5 which is shaped in side elevation as is shown to good advantage in Fig. 1; that is to say, said element 55 is formed from heavy wire, or rod material, and it includes an upwardly extended portion Ida and a forwardly extended, upwardly inclined portion i5b. The element I5 is formed from a single length of material, there being a loop H6 at the top of the upwardly extended portion i511 from which outer portions ll extend downwardly (see Fig. 2). The lower portions of the outer portions l? are flared slightly, as is shown at I? in Fig. 2, and extended forwardly from the lower ends of these flared portions ii is a pair of transversely spaced, upwardly inclined portions !8. From the forward ends of the portions l3 upwardly extended, convergent portions 59 are extended, and 'extended rearwardly and downwardly from the upper ends of said convergent portions 85 is a pair of closely related, parallel portions 23, aid portions 29 merging into portions 2! which are extended rearwardly in substantial parallelism with the portions it previously mentioned herein. From the rear ends of the portions 26 portions 22 are extended upwardly, said portions 22 throughout their upper portions being interposed between the portions ll of the element i5 and terminating within the loop it at the upper ends of said portions H, as is shown in Fig. 2.

The element i5 is provided at its upper end with a cap 23 which embraces upper parts of the portions ll, the loop l6 thereof, and upper parts of the portions 22. Likewise at a point beneath the cap 23, a band 24 is provided which embraces parts of the portions ii and parts of the portions 22. Additionally, the lower end portions of the portions ll" re disposed in vertical parallelism, and a band 25 is provided which includes outer portions 26 (see Fig. 4) wh'ichembrace said lower parts of said portions ll, said band 25 including an inner portion Zl which embraces parts of the portions 22. The element l5 includes, also, hinge members 25 which are soldered, or otherwise secured, to the spaced portion 18 of said element, said hinge members comprising upper portions '28 which embrace parts of said portions l8, and blade portions 29 which extend downwardly from said embracing portions 28'. By referring to Fig. 3 it will be noted that the blade portions 29 of the hinge members 28 project between parts of the portions I2 and i l of the supporting member I, and extended through openings formed through said blade portions 23 are the upper legs of U-shaped hinge elements 38 which are respectively soldered, or otherwise secured, to related portions 12' and M of said supporting member 1. Thus, the entire element It is supported for pivotal movement about the upper legs of the U-shaped hinge elements 30 so as to permit the upper portion of said element I 5 to move toward and from the element 5.

It will be noted that the upper portion of the element I5 is inclined forwardly slightly, as is shown in Fig. l, and that the lower end of the upwardly extended portion l5a of said element I5 normally rests on the top face of the band I .of the supporting member I. This supports the vertical portion We of said element E5 in position to provide an air gap G of the proper width between the lower portion 527 of the element 5 and an adjacent part of the vertical portion 15a of the element 15. Under certain conditions, as will presently appear herein in greater detail, the upper portion of the element l5 maybe moved away from the element 5 to increase the width of the air gap G, the element It pivoting about the upper legs of the U-shaped hinge elements 3% at such time.

The insulator l of the surge arrester A has suitably fixed thereto at its lower end a ground terminal 3| to which is connected by a suitable connector 32 an outgoing or ground conductor Cb. The ground terminaltl has fixed thereto a contact arm 33 which is formed from a length of heavy wire, said contact arm 33 being provided with, a pair of transversely spaced, coiled portions 34 from the centers of which rearwardly projected portions 35 are extended, and said rearwardly extended portions being provided with an upwardly extended loop 35 at their rear ends which contacts with the ground terminal. 3 I. The contact arm 33 is secured to the ground terminal 3! by means of a bolt and nut assembly 37, the shank of the bolt of said assembly being extended through the loop 36 and through an aperture formed through the ground terminal. Extended forwardly from the lower portions of the coiled portions 3 1 of the contact arm 33 is a pair of portions 38 which converge at their forward ends, as shown in Fig. 5, to provide a pair of closely related, forwardly extended portions 39, said portions 3% at their forward ends having rearwardly bent gripping portions ii! which are flared at their rear ends. The contact arm 33 is provided at its forward end with a cap 41 which embraces the forward portions of the portions 39 and t9, and, also, the rear portions of the portions 39 are embraced by a band 22, said cap and band retaining the portions of the contact arm 33 which are embraced thereby in their proper related positions.

The surge arrester A includes, also, a surge link d3, said surge link comprising a tube structure 34 within which is arranged a pair of electrodes that are spaced apart to provide a gap within said tube structure (not shown). Additionally, the surge link d3 includes cables t5 which extend in opposite directions from the opposite ends of the tube structure, said cables being provided at their outer ends with eyes d6 that are adapted to receive portions of a tool adapted for use in applying the surge link to the surge arrester. In assembling the surge link 43 with the surge arrester A, the lower cable 45 of said surge link is drawn into one or the. other gripping structures of the contact arm 33 provided by the gripping portions 1 9 and adjacent parts of the portions 39 of said contact arm 33, said lower cable being gripped by certain of the parts referred to as is shown in Fig. 5. The surge link 43 is then elevated and the upper cable is passed between the portions 29 of the element l5 and is moved rearwardly of said portions 29 to a point where said cable is gripped between the portions 2| of said element it, as is shown in Fig. 4. When the surge link is elevated as described the outer end of the contact arm 33 is elevated and this tensions the coiled portion 34 of said contact arm 33 and stores up force therein which tends to move the outer end of said contact arm in a downward direction. It is obvious that the tendency of the outer portion of the contact arm 33 to move downwardly retains the element l5 in its normal position because the element I 5 and the contact arm 33 are connected by the surge link 43.

When, in the use of the improved surge arrester disclosed herein, a surge is imposed on the protected circuit by lightning, or other causes, an electrical arc is established across the gap G, which normally keeps potential off of the surge link 43, and another electrical arc is established across the gap (not shown) within the tube struc ture of said surge link 43, said surge passing to ground by way of the contact arm 33, the ground terminal 3i, and the conductor Cb. A follow-up power arc will be established across the gap within the tube structure of the surge gap 43 and this follow-up power arc will be extinguished. within the tube structure of the surge link. If, however, the surge link fails to properly extinguish the power arc, the continuance of the arc will destroy the tube structure of the surge link by burnin same so that its opposite end portions are separated, and when this occurs the outer end portion of the contact arm 33 will swing downwardly in response to force imparted by the tensioned, spirally coiled portions 34 of said contact arm 33 to quickly jerk the tube structure of the surge link apart, and thereby free the surge arrester A from ground by creating a substantial air gap which will prevent reestablishment of an arc.

If a surge imposed on the protected circuit is so heavy that accompanying forces tend to increase the width of the air gap G, as was previously explained herein, such forces will cause the element to swing on its hinge structures so as to move the upper portion of the element IS in a direction away from the element 5 to widen the air gap G, the element I5 being returned to its normal position when the surge has been arrested by the resilient contact arm 33 whose outer end portion is elevated when the element I5 is moved on its hinge structures to increase the width of the air gap G. It is obvious, therefore, that passage of a heavy surge across the air gap G will not permanently alter the width of the air gap, as was frequently the case heretofore, the proper setting of the air gap being re-established after each passage of a heavy surge which temporarily widens the air gap.

I claim:

1. A surge arrester comprising an insulating supporting structure, a pair of spaced apart elements supported by said insulating supporting structure and providing an air gap therebetween, one of said elements being mounted for movement with respect to the other element whereby said movably mounted element may be moved by force traversing said air gap so as to increase the width of said air gap, a resilient contact arm, and means comprising a surge link connecting said movably mounted element and said resilient contact arm whereby said resilient contact arm serves to retain said movably mounted element in a position where an air gap of normal width is provided.

2. A surge arrester comprising an insulating supporting structure, a pair of spaced apart elements supported by said insulating supporting structure and providing an air gap therebtween, one of said elements being mounted for movement with respect to the other element whereby said movably mounted element may be moved by force traversing said air gap so as to increase the width of said air gap, means for pivotally supporting" said movably mounted element, a resilient contact arm, and means comprising a surge link connecting said movably mounted element and said resilient contact arm whereby said resilient contact arm serves to retain said movably mounted element in a position where an air gap of normal width is provided.

3. A surge arrester comprising an insulating supporting structure, a pair of spaced apart elements supported by said insulating supporting structure and providing an air gap therebetween, one of said elements being @edly supported and the other thereof being mounted for movement with respect to said fixedly supported element whereby said movably mounted element may be moved by force traversing said air gap so as to increase the width of said air gap, a resilient contact arm, and means comprising a surge link connecting said movably mounted element and said resilient contact arm whereby said resilient contact arm serves to retain said movably mounted element in a position where an air gap of normal width is provided.

4. A surge arrester comprising an insulating supporting structure, a pair of spaced apart elements supported by said insulating supporting structure and providing an air gap therebetween, one of said elements being fixedly supported and the other thereof bein mounted for movement with respect to said fixedly supported element whereby said movably mounted element may be moved by force traversing said air gap so as to increase the width of said air gap, means for pivotally supporting said movably mounted element, a resilient contact arm, and means comprising a surge link connectin said movably mounted element and said resilient contact arm whereby said resilient contact arm serves to retain said movably mounted element in a position where an air gap of normal width is provided.

5. A surge arrester comprising an insulating supporting structure, a pair of spaced apart elements supported by said insulating supporting structure and providing an air gap therebetween, one of said elements being fixedly supported and the other thereof being mounted for movement with respect to said fixedly supported element whereby said movably mounted element may be moved by force traversin said air gap so as to increase the width of said air gap, means for pivotally supporting said movably mounted element, a resilient contact arm, and mean comprising a surge link connecting said movably mounted element and said resilient contact arm whereby said resilient contact arm serves to retain said movably mounted element in a position where an air gap of normal width is provided, said surge link being provided with cables at its opposite ends and said movably mounted element and said resilient contact arm having gripping portions which grip said cables.

CHARLES ADIN FOX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,179,722 Heinritz Apr. 18, 1916 2,108,465 Austin Feb. 15, 1938 2,272,370 Fox Feb. 10, 1942 2,327,865 Brown Aug. 24, 1943 2,427,460 Johnson Sept. 16, 1947 

